At one of my previous companies, once we reached significant volume, Cybersource asked us for a material percentage of our transaction volume as a reserve, otherwise they would shut us down. I would never use them again as a processor.
I've used them for a customer processing more than 20 million dollars/year and we didn't have that. The merchant account does take a small percentage as a rolling reserve though (3% if I remember correctly).
In term of programing, I much prefer dealing with Braintree but Cybersource is not too bad (not the worse gateway I've dealt with, less issues tha Authorize.net)
